Shopkeepers display refrigerated or frozen products in temperature-controlled display cases, such as refrigerators with glass display doors or open-air, “coffin,” coolers. The refrigerators and freezers are referred to herein as “refrigerators.” Changes in temperature and humidity in the surrounding area causes condensation and frost to build up on the refrigerators. This obstructs visibility of the products and can cause unsafe conditions as the condensation falls to the floor. As a result, it is desirable to prevent the build-up of condensation and frost on refrigerators.
To combat condensation and frost, heaters are installed in refrigerator doors and frames, which raise the temperature of the door or frame sufficiently to eliminate condensation. Typically these heaters run constantly, but devices that control whether the heaters are on or off are known in the art. They are referred to generally as anti-sweat controllers. One anti-sweat controller known in the art attaches one or more condensation sensors to the refrigerator door and turns on a door heater when condensation is sensed. Traditionally, a single control box is used to control all the sensors of a given refrigerator. These devices fail, however, to prevent condensation because the heater is not activated until after condensation is sensed. Another version uses a humidistat to sense humidity in the aisle and, when the humidity goes above a given level, the heater is turned on, often regardless of whether condensation is actually present. This increases energy consumption because the heater is either constantly on or turned on unnecessarily. It would be desirable to prevent condensation with the minimum amount of heat, and consequent energy expenditure, necessary.
The anti-sweat controllers known in the art also suffer from the fact that they are hardwired into the local power source, which results in difficult access for repair and replacement because the anti-sweat controllers must be unwired each time they are removed and rewired each time they are reinstalled. If the anti-sweat controller breaks, the fact that the system is integral with the local power source may cause the shopkeeper to be unable to set the system to keep the heaters on until a qualified repairman fixes the problem. Further, the dismantling and reconstruction cause safety issues while obstructing customer access to the refrigerators. It would be desirable to provide an anti-sweat controller that is easier to install, repair and replace and that provides a means for the shopkeeper to mitigate problems if a controller fails.
The controller box controls a number of factors that must be set correctly to reduce energy consumption and eliminate condensation, such as sensitivity of the sensor and how long the heater stays on or off once signaled. To date, these factors have been measured and controlled by manually adjusting various currents and voltages on each control box with a multimeter. For a store with multiple refrigerators and multiple anti-sweat controllers, the multimeter must be plugged into each separate controller in order to adjust the entire system. Detecting the specific location of an electrical failure is frustrating and time consuming due to the need to test each separate device. Balancing the system becomes tedious. As a result, it is desirable to reprogram, monitor, and control an anti-sweat controller system without having to plug into each control box on each refrigerator and without having to make on-site visits to each store.
Therefore, it is an object of this invention to provide door heating where condensation has not yet been detected but is anticipated. It is another object of this invention to provide ease of programming, repair, and reinstallation. It is a further object to provide a system that can be set to a heater-on state if a problem arises with the anti-sweat controller. Another object of this invention is to provide a mobile device that tests and programs all the devices of the system by connecting into only one portion of the system. It is an additional object of the invention to provide remote monitoring and control.